[Triggers] Item Must Have # or (time) worth of values

[Clontarf[X]]

I am trying to do the following;

{item.regexp(60d,"UnAssigned",eq)}=1
 and
{item.havedata(60d)}=1

I don't yet have 60 days worth of data for this item, so this trigger should always be false. However, once I do have 60 days of data, I want it to be true as long as the conditions are true.

Obviously .havedata() is a made-up function. I can't use .nodata(5184000) because that only checks whether we have any (or no) data in the given period of time, not that we have a consistent 60 days of data.

The .regexp() function seems to consider whether data is available in the given period, but not for the entire period.

Any ideas on how we can ensure we have an amount of data (either number of samples, or time) before saying the trigger is true?